Interobserver correlation
To assess interobserver correlation, the intraclass correlation
coefficient was calculated based on the measurements carried out for
each patient and each area by two independent observers. The results
showed an adequate correlation with values greater than 0.8 in all
cases:
Area measurement AF <0.5mV: intraclass correlation coefficient
0.88 p<0.001
Area measurement AF <0.3mV: intraclass correlation coefficient
0.92 p<0.001
Area measurement SR <0.5mV: intraclass correlation coefficient
0.89 p<0.001
Area measurement SR <0.3mV: intraclass correlation coefficient
0.86 p<0.001
Follow-up The mean follow-up time was 25 ± 12 months. Ten patients
(43.5% of all patients) presented arrhythmic recurrence at
post-ablation follow-up. Among patients who had recurrence, 8 of them
presented AF (80% of the patients with recurrence), whereas 2 of them
presented atrial flutter (20% of the patients with recurrence)
Median arrhythmia free survival at follow-up was 25.3±3.7 months.
For 0.5 mV threshold, mean percentage of LVA in maps in SR was 4.2%
whereas it was 15.6% in maps in AF. 2 tests were performed to assess a
possible relationship between fibrosis and arrhythmic recurrences.
For the percentage of LVA in maps in AF the Pearson linear correlation
test was r=0.39 with a value of p closed to statistical significance
(p= 0.06). For maps in SR, the result was r=0.189, clearly not
significant (p=0.388).
We studied the relationship of the percentage of LVA greater than 5%
with arrhythmic recurrences. In AF, both variables showed almost
significant association (p=0.06): 56.3% of patients that presented a
percentage of LVA greater than 5% had arrhythmic recurrences whereas
only 14.3% of patients with a percentage of LVA less than 5% had a
recurrence. In SR, the result was not significant (p=0.382).